In recent years, flexible printed circuit boards have been often used for connection between motors and external circuits. In the flexible printed circuit board, only soldered portions are structurally fixed and connected. Thus, the soldered portions tend to be moved when the flexible printed circuit board is pulled or the like by motor vibration or external force. Therefore, the soldered flexible printed circuit boards have been in danger of disconnection or fracture due to forces applied on their soldered portions. In particular, there are large possibilities of disconnection or fracture because of an acute angled edge of a solder fillet.
Conventionally, many means for reinforcement fixation or the like with adhesive tapes and adhesive agents have been employed to prevent disconnection or fracture. However, in the case of using the adhesive tapes, there are problems of an increase in cost for raw materials, an increase in cost for additional works such as stripping of release paper, generation of waste materials of release paper, and the like. Alternatively, in the case of using, the adhesive agents, there are problems of unstable quality, difficulty in control of the adhesive agents, time and facility requirements for dryness, tendency of the adhesive agents to adhere to an area other than adhesion-requiring areas, and the like. Furthermore, a method for reinforcement fixation using an adhesive tape or an adhesive agent has problems of time required for dryness as well as difficulty in long time maintenance of stable quality.
On the other hand, Japanese Unexamined Patent Application Publication No. 2002-119004 (Patent Literature 1) discloses a motor (FDD spindle motor) for preventing, a soldering contact from being disconnected due to pulling a flexible printed circuit board 3 without requiring reinforcement with tape or adhesion. Specifically, as shown in FIG. 5, the motor is configured such that the flexible primed circuit board 3 is engaged with an arm-shaped protrusion 7 that protrudes from an edge portion of a printed circuit board 1 constituting a stator of a motor. Such a configuration prevents the soldering contact from directly being subjected to pulling force even when the flexible printed board 3 is pulled. Here, reference numerals of the elements in this paragraph correspond to those given in Japanese Unexamined Patent Application Publication No. 2002-119004 (Patent Literature 1) but different from those in the present invention which will be described later.
Furthermore, Japanese Unexamined Patent Application Publication No. 10-174410 (Patent Literature 2) discloses a linear motor configured to prevent a flexible printed circuit board 8 from being subjected to local force application. Specifically, as shown in FIG. 6, a clamp 12 is mounted on a top surface of a bobbin 6 and made of the same heat-resistant electrical insulating resin as that of the bobbin 6, so that the clamp 12 pushes one end of the flexible printed board 8 against an upper end surface 6A of the bobbin 6 via a cushion 13. The cushion 13 is formed of a rubber plate or the like. Here, reference numerals of the elements in this paragraph correspond to those given in Japanese Unexamined Patent Application Publication No. 10-174410 (Patent Literature 2) but different from those in the present invention which will be described later.
However, the means disclosed in Japanese Unexamined Patent Application Publication No. 2002-119004 (Patent Literature 1) has problems of difficulty to mount the arm-shaped protrusion near a terminal of a motor due to a cylindrical shape of the motor and poor expectations in effects of preventing disconnection or fracture of the flexible printed circuit board even if the protrusion is mounted. Furthermore, there is another problem in that some of protruded portions for locking the flexible printed circuit boards are fixed in place and not independently removed when any repair is needed. The means disclosed in Japanese Unexamined Patent Application Publication No. 10-174410 (Patent Literature 2) has problems that there is no play at all because the flexible printed circuit board is tucked down by the clamp via the cushion and that versatility in installation of the flexible printed circuit board or the like is actually poor.